Deworming

Thoughts on Deworming

By Kristy Brawn DVM

Reprinted from The Orgler, Wisconsin Organization of Llama Enthusiasts, February 2007

Parasite control has become a looming issue in our industry and ever-present questions at veterinary panel discussions. Parasite control programs vary based on the density of population (number of animals in a given area), the length of time that species has been on the same pastures (virgin pastures versus overgrazed yards), soil types (sandy soils are less conducive to parasite larvae/egg arrival than are heavy soils), parasites with other host species or parasites endemic to an area (meningeal worm and liver flukes) and "animal traffic" (a closed herd when there are no new animals and no movement versus a herd that shows, does outside breedings, "animal dealers," etc).

A few basic thumb rules:

Where there is grass, there are worms.

The more animals in an area, the higher your parasite exposure.

Coccidia become more of a concern the longer a species is in an area.

The more animals move on/off your farm, the more at risk you are for parasite infestation.

Formed stool does not mean your herd is parasite-free.

Fecal exams are an important management tool.

Use appropriate drug dosages--do not under-dose!

Proper doses and product rotation decreases the likelihood of resistance.

I hate to give a parasite control strategy for everyone to follow because it just won't fit every herd. If you have meningeal worm as a threat in your area, then your deworming must be more aggressive and timely and the importance of product rotation is far more important. If you have sandy soil or conditions are arid, you can get by with far fewer dewormings and a different rotation of products.

Generalities:

Meningeal threat - whitetail deer and snails/slugs are a part of the lifecycle of meningeal, so conditions conducive to snails/slugs increase your risk (heavy soils, standing water, leaf litter, down grasses, shady area, etc). Estimated 30-100 days for parasite to reach the spine.

Plan:

Deworm at 4-week intervals with Ivermectin products or 6-week intervals with Dectomax to kill parasite migration. Start with spring thaw and discontinue with 6" frost in winter or snow cover. Some plans have been suggested to use strategically timed doses of Avermectins (wet spring and fall) - this does not work in heavy infested areas - I did a test group for this strategy and had meningeal infections from April to December - decide if the value of the animal is greater than the risk of infection.

It is imperative to use a different family of dewormers 2-4 times per year to kill parasites not sensitive to the Avermectin class drug (Ivo and Decto) - Fendbendazole or Albendazole both also kill the larvae and are more effective against many of the internal parasites. The number of dewormings with these products varies based on stocking density and fecal exam results.

Other topicals as needed for specific parasites - ask your veterinarian for doses - in general if it is safe for use in lactating cattle, it will likely be safe for camelids, but check first!

Coccidia:

Amprolium (Corid) at label dose for 7- 10 days

Sulfaquinalones at label dose for 7-10 days

Deccox at sheep dose used strategically for control

E. mac - different drugs apply

Fecals, fecals, fecals!!!

The only way to know if you are doing a good job with your internal parasite control is to run routine fecal exams. Centrifuge concentration methods of fecal exam are needed to be sure we identify all possible eggs. Routine small animal flotations may miss many egg types and quantities - with the centrifuge method we not only identify the types of eggs present, but also get an estimate of eggs/gram and use this to assess your infection level. Composite tests can be run on groups - routine samples can be run anytime to assess infestation levels. Samples should be taken 10-14 days post-deworming to be sure that you are eliminating parasites. Note: if a sample is found positive on an individual animal, the whole group should be treated even if no other animals show symptoms.